Lagarosiphon Harv.
  • Harv., J. Bot. (Hooker) 4: 230 (1842)

This taxon is accepted by WCS higher taxonomy

General Description

Dioecious, submerged, freshwater, perennial herbs. Roots simple, adventitious, without root hairs, arising from nodes. Stems elongate, stoloniferous or erect, filiform to terete, simple or branched from axils; branches 1 per axil. Leaves sessile, spirally arranged, subopposite or in whorls, linear to lanceolate, shortly acuminate to subobtuse, patent to strongly recurved, firm or flaccid, with 2 apical spines, often with 2 bands of sclerenchyma fibres on either side of midrib and 2–6 rows of submarginal sclerenchyma fibres; venation reduced to midrib only; margins green or hyaline, denticulate. Stipules 0. Nodal scales 2 per leaf, linear to widely ovate, with entire or papillose margins. Flowers unisexual. Male spathe solitary in leaf-axil, sessile, ovate to suborbicular, toothed, containing up to 40 flowers. Male flowers shortly pedicellate, becoming detached and floating before anthesis; sepals and petals 3, oblong-ovate to ovate, obtuse or cucullate, usually reflexed at anthesis; stamens 3; anthers 4-thecous, fixed at right-angles to the filaments; filaments filiform, spreading horizontally; staminodes often present, 3, filiform, papillose, longer than the stamens, usually joined at the apex and functioning as a sail. Female spathe solitary in leaf-axil, sessile, narrowly ovate to ovate, toothed, 1-flowered. Female flower: sepals and petals 3, elliptic to ovate, obtuse or cucullate, usually reflexed at anthesis; staminodes 3, minute, linear; ovary 1-locular, placentation parietal; ovules 5–30, orthotropus; perianth-tube filiform, exerted laterally from the ovary near apex of the spathe, carrying perianth to the water surface; styles 3; stigmas 6, 2 per style, linear, papillose. Fruit ovate, beaked at apex, pericarp smooth, irregularly dehiscent. Seeds narrowly ellipsoid to ellipsoid, smooth, with short stipe at base, attenuate at apex.

{i}Flowers{/i} diœcious. {i}Male{/i}: spathes ovate, bifid at the apex, many-flowered; perianth 6-lobed, 3 outer lobes slightly larger than the inner; stamens 3; staminodes 2–3. {i}Female{/i}: spathes ovate or oblong, 1-flowered; perianth-tube long, very slender; limb of 6 lobes, the 3 outer slightly larger; style as long as the perianth-tube; stigmas 3, short, sometimes forked; ovules few or many, orthotropous.

Spathes unisexual. Male ovate, 2-fid at the apex, many-flowered. Calyx 3-lobed; lobes narrow. Petals 3, ovate. Stamens 3; anthers ovate. Staminodes often 2–3. Female narrowly oblong, 1-flowered. Calyx and corolla similar to those of the male. Ovary 1-celled, shortly rostrate, with 3 parietal placentas; styles 3, erect; ovules many, orthotropous. —Stems elongated, branched, clothed all over with leaves. Leaves alternate, subopposite or (in L. hydrilloides) whorled, linear or linear lanceolate. Spathes axillary, solitary.


Benth. et Hook. f. Gen. Pl. iii. 450.

in Hook., Journ. Bot. 4: 230 (1841); Wright in F.T.A. 7: 3 (1897); Symoens & Triest in B.J.B.B. 53: 441 (1983)

in Hook., Journ. Bot. 4: 230 (1841); F.T.A. 7: 2.

Distribution Map

  • Native distribution
  • Introduced distribution
Found in
  • Africa East Tropical Africa Kenya
  • Tanzania
  • Uganda
  • Northeast Tropical Africa Chad
  • Ethiopia
  • Somalia
  • Sudan
  • South Tropical Africa Angola
  • Malawi
  • Mozambique
  • Zambia
  • Zimbabwe
  • Southern Africa Botswana
  • Cape Provinces
  • Caprivi Strip
  • Free State
  • KwaZulu-Natal
  • Lesotho
  • Namibia
  • Northern Provinces
  • Swaziland
  • West Tropical Africa Burkina
  • Mali
  • West-Central Tropical Africa Cameroon
  • Central African Republic
  • Rwanda
  • Zaire
  • Western Indian Ocean Madagascar
Introduced into
  • Australasia New Zealand New Zealand North
  • New Zealand South
  • Europe Middle Europe Austria
  • Germany
  • Netherlands
  • Switzerland
  • Northern Europe Great Britain
  • Ireland
  • Southeastern Europe Italy
  • Southwestern Europe France
Not found in
  • Africa West Tropical Africa Ghana


  • 1 Govaerts, R.H.A. (2011). World checklist of selected plant families published update. Facilitated by the Trustees of the Royal Botanic Gardens, Kew.
  • 2 David Simpson (1989) Hydrocharitaceae. Flora of Tropical East Africa 0 (0)
  • 3 F.n. Hepper (1968) Hydrocharitaceae. Flora of West Tropical Africa 3 (1)
  • 4 (By C. H. Wright.) (1913) Hydrocharideæ. Flora Capensis 5 (3)

 Information From

Flora of Tropical Africa
Flora of Tropical Africa. Published on the Internet;
Flora of Tropical East Africa
Flora of Tropical East Africa. Published on the Internet;
Flora Capensis
Flora Capensis. Published on the Internet;
Flora of West Tropical Africa
Flora of West Tropical Africa. Published on the Internet;
WCS higher taxonomy
  • E All Rights Reserved
World Checklist of Selected Plant Families
WCSP 2014. 'World Checklist of Selected Plant Families. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet; Retrieved 2011 onwards
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